6,220 research outputs found
Factors Related to Teachers' Perception of Problem Solving Skills Instruction
This study aimed to: (1) ascertain the Form Two Integrated Living
Skills (ILS) teachers' perception of problem solving skills instruction;
(2) determine the relationships between the teachers' perception of problem
solving skills instruction and teacher-related variables; and (3) determine the
relationships between the teachers' perception of problem solving skills instruction
and student-related variables. The teacher-related variables were demographic
characteristics (i.e. gender, professional qualifications, teaching experience, in service
courses attended and school location), and the teachers' perception of their
own readiness for problem solving skills instruction. The student-related variables were the teachers' perception of student readiness for problem solving skills
instruction, student mastery of the ILS contents and student intellectual
capabilities.
One hundred and fifty-five Form Two ILS secondary school teachers
from the state of Negeri Sembilan served as respondents in the survey. A self administered
questionnaire using a four-point Likert scale was used. Data were.
analysed using descriptive statistics, correlational techniques and stepwise
multiple regression. The findings showed that teachers indicated that they had infused
problem solving skills into their current workshop instruction. Only two
demographic variables, school locality and the number of lessons that the teachers
taught in each week (a variable under teacher experience) had significant
correlations with the teachers' perception of problem solving skills instruction.
Positive and significant correlations were established between the overall teachers'
perception of problem solving skills instruction and teacher readiness for the
problem solving skills instruction, teachers' perception of student readiness for the
problem solving skills instruction, and teachers' perception of student intellectual
capabilities. Stepwise multiple regression analysis showed that teachers' perception
of student intellectual capabilities, teacher readiness for problem solving skills
instruction and number of ILS lessons taught each week accounted for 18 percent
of the variance in the teachers' perception of problem solving skills instruction
Superhydrophobic dyeing of orange fruit pigment on cotton knitted textile application
The pigment is the substance that changes the colour of light based on the result of selective colour absorption. Pigments are used for colouring paint, fabric, ink, food, cosmetic and other materials. The materials that chosen and developed by human for use as pigment must have special properties that make them ideal for make them colouring other materials. The pigment must be stable in solid form at ambient temperatures [1]. Pigments can be divided into two groups which is organic pigment and inorganic pigment. For inorganic pigments, the colour is comparatively less bright and these pigments are also seemed to be less rich than the organic pigments. Large amount of inorganic pigments are required to generate desired effects since these pigments have low tinting strength. The most important thing is inorganic pigment contains toxic substances that may be harm to our health and environment. The researchers are started to investigate and use organic pigment into textile application nowadays [2]
Onset of natural convection in gas-gas system induced by bottom-up transient mass diffusion
The onset of convection induced by transient mass diffusion in a stationary gas was succesfully predicted with transient instability theory and simulated using a computational fluid dynamics (CFD) scheme. 2D time-dependent simulations were conducted for bottom-up diffusion of a light gas in a stagnant heavy gas. The results of simulations were used to calculate the transient Rayleigh number adopted from the theory of Tan and Thorpe (1996 and 1999). The average transient maximum Rayleigh number from simulations is 707, which is close to the theoretical value of 817 for analogous bottom heating with constant heat flux. The simulated critical times of the onset of convection were in reasonably good agreement with the predicted values from theory
Analysis of floating refuse along the Gombak River
Data were collected on the types and weights of floating refuse along the Gombak River off Jalan Sentul in Kuala Lumpur over a period of 6 months. Based on the samples taken, the refuse was divided into different categories and their proportions by weight and average bulk density were estimated. It was found that the largest component by weight (42%) of the refuse consisted of cans, containers and other products made from metal. The average bulk density of the wet refuse was about 100 kg/m 3 . Suggestions
are also made with regards to the best methods to collect the floating refuse and to clean up the rivers in the Kuala Lumpur City area based on the characteristics of the waste and an assessment of the various methods being currently tested
The onset of convection caused by buoyancy during transient heat conduction in deep fluids
The onset of convection in a thermal layer generated by transient heat conduction in deep fluid is examined. It is generally accepted that buoyancy driven convection predominates in deep fluids while surface tension driven convection can occur only in very thin layers of liquid. The occurrence of buoyancy convection can be predicted from conventional linear stability analysis for steady-state heat conduction. Its results are summarised in terms of critical Rayleigh numbers. The point of instability in transient heat conduction is, however, less well understood. Its onset in deep fluids is determined by the mode and rate of cooling. In this paper, the judicial application of transient heat conduction equations and a newly defined transient local Ra with the appropriate boundary conditions has allowed the tracking of the time and spatial development of local hydrodynamic equilibrium to the point of instability. The onset of convection can be predicted from the maximum transient Ra whose values are the same as those previously obtained by linear stability analysis for the same boundary conditions. The critical times and critical depths for stable diffusion in fluids (i.e. without convection) can thus be determined accurately. Agreement with observed values from the literature is very good. The mode and rate of heat conduction are confirmed to be the controlling factors in determining the time of onset of convection
Parental Attitude and Parental Intervention Strategies on Digital Media Usage Among Young Children
Technology-focused parenting has evolved to provide a constantly updated digital experience for the new digital populations while parents mitigate the risks of digital media exposure in this modern society. This study explores parental attitude on the impact of digital media and their respective parental intervention strategies. There were five parents recruited through purposive sampling technique and they participated in in-depth interview. Parents generally hold positive attitude towards digital media. They apply different parental strategies for children’s media activities and its contents. This study addressed relationships pertinent to current parental strategies, media and child’s factors. Considerable possibilities and patterns to nurture young children with digital media has been elucidated through uncovering parents’ perspectives and challenges
On predicting mantle mushroom plumes
AbstractThis study investigates the mechanism of formation of convection plumes of mushroom shape in sub-solidus mantle and their prediction. The seismic-tomographic images of columnar structures of several hundreds kilometers in diameter have been reported by several researchers, while the much cherished mushroom-shaped plume heads could only be found in computational geodynamics (CGD) models and simple small-scale laboratory analogue simulations. Our theory of transient instability shows that the formation of convection plumes is preceded by the onset of convection caused by unsteady-state heat conduction at the boundaries, from which filamentous plumes first appear. The plumes generated at the Core Mantle Boundary (CMB) and lithosphere rising and falling through the mantle have been predicted simply with our theory for various heat fluxes and viscosities, which still remain uncertain amongst geoscientists. The sizes of mushroom plumes in the sub-solidus mantle caused by heat fluxes of 20 and 120 mW/m2 at the CMB are found to be 1842 km and 1173 km with critical times over 825 Myr and 334 Myr respectively. They are comparable to some large continental flood basalt provinces, and they number between 17 and 41. The thickness of the thermal boundary layers at the CMB from which convection plumes evolved are found to be 652 km and 415 km for 20 and 120 mW/m2 respectively.Top cooling may produce plunging plumes of diameter of 585 km and at least 195 Myr old. The number of cold plumes is estimated to be 569, which has not been observed by seismic tomography or as cold spots. The cold plunging plumes may overwhelm and entrap some of the hot rising plumes from CMB, so that together they may settle in the transition zone
Large deformation, damage evolution and failure of ductile structures to pulse-pressure loading
In this paper, a model is developed for an elastic perfectly-plastic structural beam system subjected to general pulse-pressure loadings - this may be either impulsive or non-impulsive - which is capable of capturing large non-linear deformation, ductile damage evolution and its consequential failure. The proposed model is an extension of Schleyer and Hsu (2000) by incorporating interactions between bending, membrane stretch and transverse shear in the fully plastic stress state, and uses damage mechanics to capture the loss of integrity at the supports and the subsequent beam detachment. Predictions by the model were validated against existing experimental data from literature and to three-dimensional finite element models developed in this paper. Parametric studies were performed to elucidate the effects of loading duration on the mode of deformation by the beam and the critical conditions governing their transition. The efficacy of Youngdahl’s (1970; 1971) technique on desensitising pulse shape effects is also investigated using different pressure pulse profiles and it will be shown that the technique is successful only for monotonically decaying pulse-pressures
The influence of deformation limits on fluid-structure interactions in underwater blasts
This paper revisits a classical fluid-structure interaction (FSI) problem on the momentum and energy transfer to a structure from an underwater blast. Hitherto, the majority of analytical models assume a rigid (non-deformable) and free-standing (unsupported) structure where resistance to its translational motion - apart from that offered by its inertial mass - comes from ‘ad-hoc’ backing spring(s) introduced to simulate compression of the fluid medium and/or the resistance to transverse deformation encountered by a real structure. These limitations/assumptions are relaxed in this paper by adopting a physically realistic fully-clamped ductile beam system that takes into account large elasto-plastic deformation, limits to material deformation, boundary compliance and boundary failure; the analytical framework was developed previously by Yuan et al. [1]. By coupling the fluid (water) domain to the analytical model of the ductile beam system, the momentum and energy transferred by the blast wave are critically re-evaluated for non-impulsive loading régime; in particular, on how the beam’s deformation mode and boundary compliance affects fluid and structure interaction, up until the point of complete beam detachment from its supports. Detailed finite-element models were also developed to simulate the interactions between the fluid and structural beam where predictions were in good agreement with those by the analytical model. Sensitivity analyses were carried out that offer new insights on the influence of the beam’s aspect ratio and inertial mass
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